Why are my teeth sensitive? Causes and treatments

A sharp twinge from ice cream, a cold drink, or even a breath of winter air is one of the most common complaints we hear. Sensitivity is not a diagnosis. It is a symptom, and the useful question is what is causing it, because the treatment depends entirely on that.

What is actually happening

Under the enamel is dentine, a layer threaded with thousands of microscopic tubules that run to the nerve. Enamel and, on the roots, gum tissue normally seal those tubules off. When either barrier is lost, cold, heat, sweet or touch reaches the nerve directly and it fires. Almost every case of sensitivity comes down to exposed dentine somewhere.

This is why the tooth has only one way of telling you anything. The nerve inside cannot distinguish cold from pressure from acid — every stimulus arrives as pain. It is also why sensitivity is such an unreliable guide to severity: a tiny area of exposed root can be agonising, while a large cavity can be silent.

The common causes

Gum recession. The most frequent cause in adults. Root surfaces have no enamel, only a thin layer of cementum that wears quickly once exposed. Recession follows gum disease, over-vigorous brushing with a hard brush, grinding, and sometimes just age. See gum recession.

Enamel wear. Acid from soft drinks, sports drinks, wine, citrus and reflux softens enamel; brushing straight afterwards strips it. Grinding and clenching wear it mechanically. Once enamel is thin, dentine is close to the surface.

A cracked tooth or cracked filling. Sensitivity to cold and a sharp pain on biting that releases when you let go is the classic pattern. This one matters, because cracks progress. See broken tooth.

Decay. Early decay under an old filling or between teeth often announces itself as sensitivity to sweet things before anything hurts.

Recent dental work. A new filling or crown can be sensitive to cold for a few weeks while the nerve settles. A filling left slightly high in the bite causes sensitivity and tenderness until it is adjusted, which takes a minute.

Whitening. Temporary and expected. See sensitivity after whitening.

Generalised sensitivity with no obvious cause is usually a mix of mild recession and enamel wear, and responds well to the simple measures below.

What the pattern tells you

The detail matters more than the intensity, and it is the fastest way to work out whether this is a toothpaste problem or an appointment.

What you notice	Usually points to
Brief twinge to cold, gone the instant it is removed	Exposed dentine — recession or enamel wear
Sharp pain to sweet things	Early decay, or an exposed root surface
Sharp jolt on releasing a bite	A cracked tooth
Pain lingering 30 seconds or more after cold	An inflamed nerve — needs assessment
Worse to heat, eased by cold	Advanced pulp problem — see us promptly
Several teeth at once, both sides	Generalised wear, grinding, or acid erosion
One tooth only, getting worse	Something specific. Have it looked at
Sore to bite on, feels raised	Possible infection or a high filling

Duration is the single most useful thing to notice. Sensitivity that stops the moment the stimulus goes is a dentine problem. Pain that outlasts the trigger suggests the nerve itself is inflamed, and that changes the treatment from a toothpaste to a filling or root canal treatment.

Sensitivity at different ages

The likely cause shifts across a lifetime, which is worth knowing because the same symptom points somewhere different at 20 than at 60.

Age	Most likely causes
Children and teenagers	Newly erupted molars; enamel defects present from formation; acidic drinks; orthodontic movement
Twenties and thirties	Acid erosion from diet; whitening; over-brushing; wisdom teeth
Forties and fifties	Recession; grinding wear; cracked teeth; ageing fillings
Sixties onward	Root surfaces exposed by recession; dry mouth from medication; root decay; wear accumulated over decades

In children, poorly formed enamel on the first permanent molars is more common than most parents expect. It looks like creamy or brown patches, the teeth are sensitive out of proportion to their appearance, and brushing them hurts — which then makes everything worse. It is worth having looked at rather than put down to fussiness.

Sensitivity after dental treatment

Some is normal, some is not, and knowing which saves an anxious week.

After	What is normal	When to call us
A filling	Cold sensitivity for days to a few weeks, settling	Pain on biting, or it is worsening after two weeks
A professional clean	Mild sensitivity for a few days, especially where there is recession	It persists beyond a couple of weeks
Deep gum treatment	More sensitivity as roots become cleaner and more exposed	It is severe or not settling after a month
A crown	Some sensitivity while the tooth settles	Lingering pain, or pain to heat
Whitening	Zingers and cold sensitivity for one to three days	It lasts beyond a week
Braces or aligners	Tenderness for a few days after each adjustment or new tray	Sharp sensitivity in one tooth

The short version: settling is normal, worsening is not.

What you can do at home

Sensitivity toothpaste containing potassium nitrate or stannous fluoride, used twice daily for at least two to four weeks. It works by calming the nerve or plugging the tubules, and it needs consistency. Rub a little onto the worst spot and leave it, rather than rinsing it all away.
A soft brush and a light grip. Small circles at the gumline, not scrubbing. An electric brush with a pressure sensor helps if you press hard without noticing.
Do not brush within thirty minutes of anything acidic. Rinse with water, chew sugar-free gum, and brush later.
Limit acidic drinks, and use a straw for the ones you keep.
A night splint if you grind. See occlusal splints and night guards.

If four weeks of this makes no difference, or the sensitivity is in one tooth rather than general, it needs to be examined.

Using sensitivity toothpaste properly

Most people who say it did not work were not using it the way it works.

Brush with it twice a day, and then spit without rinsing — rinsing washes away the active ingredient before it has done anything
Smear a little directly onto the sensitive spot with a fingertip at bedtime and leave it there overnight. This is the step that makes the difference
Give it two to four weeks. These products work cumulatively, not on contact
Keep using it. Sensitivity commonly returns within weeks of stopping, because the underlying exposed dentine has not gone anywhere
Do not use a whitening toothpaste at the same time — most are abrasive, which works against you

What does not help

Worth naming, because these come up constantly and some of them actively make sensitivity worse.

Charcoal toothpaste — abrasive, and abrasion is one of the causes we are trying to remove
Brushing harder or more often — the instinct is understandable and it is the wrong direction
Baking soda used neat — abrasive on already thin enamel
Alcohol-based mouthwashes — drying, and drying raises decay risk
Acidic "natural" rinses, including anything lemon-based — acid is the problem, not the cure
Avoiding the dentist until it settles — the causes that settle on their own and the causes that get worse feel identical at the start

What happens at the appointment

We ask about the pattern — which teeth, what triggers it, how long it lasts, when it started, and what has changed recently in diet, brushing, medication or stress
We examine each tooth, looking for recession, wear facets, exposed root surfaces, cracks, leaking fillings and decay
We test the suspect teeth — cold, and sometimes bite testing on individual cusps, which is how a cracked cusp is usually found
X-rays where decay between teeth, under a filling, or a problem at the root tip is possible
We tell you what we think it is, including when the honest answer is generalised dentine sensitivity with no single culprit
We treat the cause where there is one, and start desensitising measures where there is not

Most people leave the first appointment with an explanation and a plan. Where a crack is suspected but not yet visible, the plan is sometimes to protect the tooth and review it, because early cracks genuinely can be invisible.

What we can do

The first step is finding the cause: examination, checking each tooth for cracks and recession, testing which teeth respond, and X-rays where decay or a crack is suspected.

Fluoride varnish or a desensitising agent painted onto exposed root surfaces, repeated at check-ups if needed
Bonding a thin layer of composite over an exposed or worn root surface
Replacing a leaking or cracked filling, or adjusting a high one
A crown to hold a cracked tooth together
Root canal treatment where the nerve is inflamed beyond recovery, which is uncommon and is a last resort, not a first one
Gum grafting for significant recession, which we refer to a registered periodontist

None of these is guaranteed to eliminate sensitivity completely, and some sensitivity settles on its own over months as the tooth lays down protective dentine from the inside. What we can reliably do is find the cause and rule out the things, like cracks and decay, that get worse if left.

Stopping it coming back

Sensitivity is usually the visible end of a process that is still running. Treating the twinge without addressing the cause means it returns.

If it is acid erosion — the fix is the diet and the timing, not the toothpaste. Sparkling water counts. So does slowly sipping anything acidic across an afternoon
If it is grinding — the splint is the treatment, and it also protects against the fractures that come later
If it is over-brushing — change the brush and the pressure. Splayed bristles within a few weeks is the tell
If it is reflux — worth raising with your GP, because the dental side is only managing the consequence
If it is recession from gum disease — treating the gums is what stops it progressing
If it is dry mouth from a medication — tell us what you take. Saliva is the defence that has gone missing, and there is a good deal that can be done about it

When it is more than sensitivity

See us promptly if pain lingers for more than a few seconds after the cold is gone, wakes you at night, is triggered by heat, comes with swelling, or stops you chewing on one side. Those point to an inflamed nerve, an abscess, or a cracked cusp, and none of those is a toothpaste problem. See toothache.

Swelling that involves the face, the floor of the mouth, or your ability to swallow or breathe is not a dental appointment. Call 000 or go to a hospital emergency department.

Questions we are asked

Is sensitivity a sign of a cavity? Sometimes, particularly sensitivity to sweet things. Often it is exposed dentine with no decay at all. The two cannot be told apart without looking.

Will it go away on its own? Frequently, yes — teeth lay down protective dentine internally over months. Sensitivity that is worsening rather than settling is the one to act on.

Does whitening cause permanent sensitivity? Not usually. It is temporary and settles within days. See the whitening sensitivity page above.

Can I just use sensitivity toothpaste forever? Many people do, and that is reasonable. It is worth having the cause identified once, so you are managing a known problem rather than masking an unknown one.

My whole mouth is sensitive suddenly — why? Common causes are a recent change in brushing, a new acidic habit, grinding during a stressful period, or a recently started medication causing dry mouth. Worth mentioning all four when you come in.

Why is it worse in winter? Cold air drawn over exposed dentine is a genuine trigger, and a common reason people first notice a problem that has been building for months.

Why only when I drink cold water, but not ice cream? Ice cream is cold but also fatty and slow — it does not reach the tooth surface the way cold water does. It is a quirk of physics, not a sign the problem is minor.

Does a filling always fix it? Only if decay or a leaking filling is the cause. Filling a tooth that is sensitive from recession does not help, which is why the diagnosis comes first.

Is sensitivity a normal part of getting older? Recession becomes more common with age, so exposed root surfaces do too. That makes it common, not something you have to accept.

Book an assessment

Victorian Dental Group is a general dental practice in Malvern East and holds no specialist registration. Where treatment is better provided by a registered specialist — gum grafting, for instance — we will refer you. We recommend a second opinion from another appropriately qualified practitioner if it would help you decide on treatment.

Victorian Dental Group — 291 Wattletree Road, Malvern East VIC 3145 · (03) 9088 5808 · book online

Read more about check-ups and hygiene or gum care.

General information only, not personal dental advice. Outcomes vary between individuals. See our disclaimer.

Why do teeth become sensitive?

Because the dentine underneath the enamel has become exposed. Dentine contains microscopic tubules running towards the nerve, so when it is uncovered, cold, heat, sweetness, acid or even a draught of air can produce a short sharp twinge. Enamel itself has no feeling — sensitivity means something has worn through it or the gum has receded off the root.

What exposes the dentine?

Gum recession, which uncovers the softer root surface — often from brushing too hard with a firm brush. Acid erosion from citrus, soft and sports drinks, wine or reflux. Grinding, which wears the biting surfaces and flexes the tooth at the gum line. Cracked or worn fillings. And temporary causes: recent whitening, a new filling settling in, a restoration sitting slightly high, orthodontic tooth movement, and hormonal gum changes in pregnancy.

When is it more than ordinary sensitivity?

This is the important distinction. Ordinary sensitivity is a sharp twinge that stops within seconds of the stimulus going away, usually affecting several teeth. Get it examined promptly if the pain lingers for minutes afterwards, comes on by itself, wakes you at night, is confined to one particular tooth, or the tooth is tender to bite on. That pattern suggests decay, a crack or an inflamed nerve, and no toothpaste will fix it.

What can I do at home?

Use a desensitising toothpaste containing potassium nitrate or stannous fluoride, and use it properly: rub a little directly onto the sensitive areas with a fingertip at night and do not rinse it off. It takes a couple of weeks of consistent use to work, and many people give up too soon. Switch to a soft brush and lighten your pressure, and use a fluoride mouthrinse if one has been recommended.

How should I change my diet?

Keep acidic food and drink to mealtimes rather than sipping through the day, use a straw, and follow with water or milk. Do not brush for at least 30 minutes after anything acidic or after vomiting — an hour is better — because softened enamel brushes away. Rinsing with plain water immediately afterwards is the better move.

Am I brushing too hard?

Quite possibly, if your brush splays within a few weeks. Hard scrubbing with a firm brush wears notches into the tooth at the gum line and contributes to recession, and both are permanent. Use a soft, small-headed brush, hold it lightly, and use small circles at the gum line rather than a vigorous back-and-forth. An electric brush with a pressure sensor helps people who cannot judge it.

What can be done at the practice?

First, finding the cause — examining for decay, cracks, wear patterns, recession and how your teeth meet. Then treatment directed at it: fluoride varnish or a desensitising agent applied to the exposed areas, sealing or restoring a worn notch, adjusting a high filling, a night splint where grinding is responsible, and addressing acid sources. A high-fluoride toothpaste can be prescribed. Where the nerve is genuinely inflamed, root canal treatment may be the answer.

When should I come in?

If sensitivity is new, worsening, or has not improved after a few weeks of desensitising toothpaste — and straight away if it matches the pattern described above. Victorian Dental Group, 291 Wattletree Road, Malvern East VIC 3145 — phone (03) 9088 5808 or email info@victoriandentalgroup.com.au, Monday to Friday 8:00am to 5:00pm.